After the close of WWII, Russian schoolchildren presented the U.S. ambassador with a “gesture of friendship” in the form of a two-foot wooden replica of the Seal of the United States. Behind the beak of the eagle was a miniscule listening device so ingeniously designed that it took eight years before a routine check unearthed it. The era of electronic bugs had begun, and it was largely thanks to the brilliant mind of Leon Theremin: musician, inventor, and prisoner in Stalin’s gulag.